How do I use an oven's fan and shelf positions properly?

Most ovens have five or six settings and most households use one. Knowing what two or three of the others do changes what the oven can produce.

Step by step

1. Know what fan does.It moves hot air around, which cooks faster and more evenly and allows several shelves at once. Reduce the recipe temperature by about 20°C when using it.
2. Know when not to use fan.Delicate bakes — soufflés, some cakes, meringues, custards — can be dried or lopsided by moving air. Conventional top-and-bottom heat is gentler for those.
3. Understand the heating elements.Top only for browning and grilling. Bottom only for crisping a pastry base. Both together is conventional. Fan plus bottom heat is excellent for pizza and quiches.
4. Use the middle shelf as the default.It is the most evenly heated position in almost every oven. Unless a recipe or a result says otherwise, put it in the middle.
5. Go high for browning.Anything that should colour on top — gratins, crumbles, the last few minutes of a roast. Heat rises, so the top of a conventional oven is the hottest part.
6. Go low for pastry and slow cooking.Bottom heat crisps a base, which is exactly what a quiche or a pie needs. It is also the right position for long, gentle braising.
7. Find your oven's hot spots.Toast a tray of bread slices and look at which browned first. Every oven has them, and knowing yours tells you when to rotate.
8. Check the actual temperature.An oven thermometer costs very little. Many domestic ovens run 10 to 20°C away from their dial, which explains a lot of consistently disappointing baking.
9. Preheat properly.Most ovens signal ready before they are fully stable. Another 10 minutes after the light goes out makes a real difference for baking.
10. Rotate part way through.Even with a fan. Turning a tray at the halfway point evens out whatever hot spots your oven has.
11. Do not overfill it.Trays that block the airflow, or a tray touching the back or sides, disrupt circulation and cause uneven cooking. Leave a gap all round.
12. Use a hot tray for pastry.Preheat a baking sheet and put the tin on it. That immediate bottom heat is the standard answer to a soggy base.
13. Keep the door shut.Opening it drops the temperature substantially and it takes minutes to recover. Use the light, and open only when you need to act.

Tips

• Middle shelf unless there is a reason. It is the most evenly heated part of almost every oven.
• An oven thermometer explains a lot of unexplained baking failures. Most ovens are not at their dial.
• The toast test maps your hot spots in ten minutes and you know it forever.

Common mistakes

• Using fan at the conventional temperature — Fan cooks roughly 20°C hotter in effect, so food browns before it is cooked through. Reduce the recipe temperature.
• Opening the door to check repeatedly — Each opening drops the temperature and it takes several minutes to recover, which is enough to sink a cake.

If it doesn't work